The Horde Application Framework is a modular, general-purpose Web application framework. It provides an extensive array of classes that are targeted at the common problems and tasks involved in developing modern Web applications.

HTTrack is an easy-to-use offline browser utility. It allows you to download a Web site from the Internet to a local directory, building recursively all directories, getting HTML, images, and other files from the server to your computer. HTTrack arranges the original site's relative link-structure. Simply open a page of the mirrored Web site in your browser, and you can browse the site from link to link, as if you were viewing it online. HTTrack can also update an existing mirrored site, and resume interrupted downloads. WebHTTrack is a Web-based GUI for HTTrack.

Mantis Bug Tracker (MantisBT) is a Web-based issue tracking system that is both simple to use and highly customisable. A plugin system allows users to easily create and add new features. MantisBT is over 10 years old and is actively developed.

phpMyAdmin is a tool intended to handle the
administration of MySQL over the Web. It can
create, rename, and drop databases,
create/drop/alter tables, delete/edit/add fields,
execute any SQL statement, manage keys on fields,
create dumps of tables and databases,
export/import CSV data, and administrate one
single database and multiple MySQL servers.

FUDforum is a templatable forum with i18n support based on PHP and either MySQL, Oracle, PostgreSQL, or SQLite. It features a user/group management system, a multi-lingual spell checker, both flat and thread message views, a private messaging system with multi-user forwarding capabilities, poll file attachments, and much more. It is an extremely fast and scalable forum that can fulfil the needs of both small and large forum operators.

LimeSurvey (formerly PHPSurveyor) is a Web
application that interacts with MySQL, MSSQL, or
Postgres to develop surveys, publish surveys, and
collect responses to surveys. Once a survey has
been created, data can be inserted into the survey
either by a "pretty" public screen which presents
each question one at a time, or by a quick and
nasty data entry screen. It includes the capacity
to generate individualized "tokens", so that
invitations can be issued to participants. It also
has the capacity to set conditions on whether
questions will display (branching), numerous
question types, and a basic statistics function.

Originally developed for the Psi project, Flyspray is an
easy to use bug tracking system for those who don't
require all the complexities of something like Bugzilla.
It supports multiple users, file attachments, and Jabber
notifications.

Alexandria is a GNOME application to help manage a
book collection. It retrieves book information
(including cover pictures) from several online
libraries, allows you to search for a book (either
by EAN/ISBN, title, authors, or keyword), can
import and export data into ONIX, Tellico, and
EAN/ISBN-list formats, generates Web pages from
your libraries, allows marking your books as
loaned, saves data using the YAML format, features
an HIG-compliant user interface, shows books in
different views that can be filtered or sorted,
and handles book rating and notes.

Roundcube Webmail is a browser-based, multilingual IMAP client with an application-like user interface. It provides the full functionality you expect from an email client, including MIME support, address book, and folder manipulation. High extensibility is granted by the plugin API and the user interface is fully skinnable using XHTML and CSS 2.